The proportion of small-to-medium sized companies that publish strong email authentication policies is smaller. Unless some other email filtering mechanism is in-place, email from spoofed senders in these domains might be delivered to users.

The remaining 91% of companies might be spoofed by an attacker. But domains with weaker email authentication policies, or no policy at all, are prime targets for being spoofed.Īs of March 2018, only 9% of domains of companies in the Fortune 500 publish strong email authentication policies. Domains with strong email authentication policies like and are protected from spoofing. However, DNS records for SPF, DKIM, and DMARC (collectively known as email authentication policies) are optional. In other words, the domain has been authenticated and therefore the sender's email address is not spoofed. Destination email organizations can also verify that the email domain has passed SPF or DKIM. The From address is the sender's email address that users see in their email client. Use email authentication to help prevent spoofingĭMARC prevents spoofing by examining the From address in messages. The rest of this article explains how these technologies work, and how EOP uses them to check inbound email. In all Microsoft 365 organizations, EOP uses these standards to verify inbound email:Įmail authentication verifies that email messages from a sender (for example, are legitimate and come from expected sources for that email domain (for example, .) Microsoft Defender for Office 365 plan 1 and plan 2Įmail authentication (also known as email validation) is a group of standards that tries to stop spoofing (email messages from forged senders).This new experience brings Defender for Endpoint, Defender for Office 365, Microsoft 365 Defender, and more into the Microsoft 365 Defender portal. The improved Microsoft 365 Defender portal is now available.

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